“The evolutionary approach to loneliness calls into question the dominant conceptualization of loneliness as an aversive condition without redeeming features,” the researchers argued. “Instead, loneliness is viewed as an aversive signal that indicates that important social connections are at risk or absent and acts as a motivational force to reconnect with others.”

In other words, feelings of loneliness are an important part of our survival instinct. Whereas other more primal survival instincts like hunger, fatigue or sexual attraction work to keep the body functioning properly and to assure reproduction, loneliness serves a much less tangible function, but one that is arguably just as important.

“Loneliness has played an important role in the evolution of the human species,” the researchers argued, because the heartbreak of solitude drives humans to interact.

Great things get done when we do them together, they argue, and without the sadness of solitude mankind might lack the incentive to deal with each other.

Psychologists have been arguing for years that stronger distinctions should be made between feelings of loneliness, isolation and “aloneness,” because not all are equally damaging.

Loneliness, in this perspective and in the argument of the APS study, is a yearning, a feeling that can compel one to make life changes and participate in productive activities. Isolation, on the other hand, is caused by a lack of contact with other individuals.

“People who spent very little time with friends and family, or at social events, were more likely to die regardless of income or health status,” according to NPR’s analysis of the UCL study.

The dangers of loneliness are manifest, according to the researchers, “when loneliness is sustained over time” and when those who feel lonely believe there is no way out.

But harnessing the power of those feelings in a constructive way is an important part of human social development. Loneliness is “not evolutionarily neutral but served to increase our survival as a species,” the study said.